Search for low mass vector resonances decaying into quark-antiquark pairs in proton-proton collisions at sqrt(s) = 13 TeV

TL;DR

This paper reports a search for low-mass vector resonances decaying into quark-antiquark pairs in proton-proton collisions at 13 TeV, using jet substructure techniques to identify potential signals within the 50-300 GeV mass range.

Contribution

It introduces a novel jet substructure method to search for low-mass vector resonances and sets the most sensitive limits to date for masses below 100 GeV.

Findings

No evidence of the resonance was observed.

Upper limits on production cross section were established.

Results constrain dark matter mediator models.

Abstract

A search for narrow vector resonances decaying into quark-antiquark pairs is presented. The analysis is based on data collected in proton-proton collisions at sqrt(s) = 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 inverse femtobarns. The hypothetical resonance is produced with sufficiently high transverse momentum that its decay products are merged into a single jet with two-prong substructure. A signal would be identified as a peak over a smoothly falling background in the distribution of the invariant mass of the jet, using novel jet substructure techniques. No evidence for such a resonance is observed within the mass range of 50-300 GeV. Upper limits at 95% confidence level are set on the production cross section, and presented in a mass-coupling parameter space. The limits further constrain simplified models of dark matter production involving a mediator interacting between quarks and dark matter particles through a vector or axial-vector current. In the framework of these models, the results are the most sensitive to date, extending for the first time the search region to masses below 100 GeV.